Too busy for lunch? That'd be 3.8 million of us!

You're not alone, with up to 3.8 million Australians saying they don't routinely take a lunch break, a new survey by The Australian Institute has revealed.

The survey, completed for beyondblue's national Go Home on Time Day, also found one in two respondents said they didn't take a lunch break because they were too busy.

Of those who said they did usually take a break for lunch, 72% said they chose to eat at their desks, cut short the break of postponed lunch until mid-afternoon.

The survey sparked a warning from beyondblue chief executive Kate Carnell, who said many bosses and workers had "lost sight" of how a break could improve their mental health and increase productivity.

"It's great that people are committed to getting the job done, but it is sensible to take a break away from your desk or the production line to exercise and think about other things," she said.

"A regular walk at lunchtime improves both your physical and mental health and you will resume work feeling refreshed."

Most respondents told the Institute that taking a break made them more productive and one in four said leaving work for a full lunch break reduced work-related stress.

Institute executive director Dr Richard Denniss said while Australia had a reputation for taking "sickies and smokos", the evidence showed otherwise.

"Lunch breaks have always been a part of modern workplaces, but in recent decades more and more people report that they are too busy or too rushed to do something as simple as walk away from their desk to eat their lunch," he said.

"While Australians used to celebrate the practice of taking a long lunch, we're now struggling to even manage a short one."